Climate Change Murchison

Climate and related environmental changes expected

The great majority of the Murchison subregion is classified by the CSIRO, according to Hobbs et al. classification as “Dry” (where the moisture index & growth index is high in warm season, low in cool season; CSIRO, 2008), and “Arid” according to ABARE (2012). In this region the most likely impacts of climate change will manifest as:

Fire will be important but limited by growth rates and grazing

More summer and autumn rain may increase suitability for new species from north and new pasture species

Potential for overgrazing high as productivity decreases with reduced annual average rainfall and increasing temperatures

Pastoralism may decline with some retirement of drying areas

Reduced ground and surface water would have big impact on agriculture and refuge dependent native flora and fauna

Salt incursions into freshwater swamps and rising salt in groundwater systems as a result of reduced freshwater/rain infiltration, along with other pressures on coastal resources including habitat availability that may be lost due to sea level encroachment

Projections

Average annual increase in temperature in the range of +1°C to +2°C by 2050

Summer +1°C to +2°C

Autumn +1°C to +1.5°C

Winter +1°C to +1.5°C

Spring +1°C to +2°C

Average annual change in rainfall to decrease by -2% to 10% by 2050

Summer -2% to 5%

Autumn -2% to 5%

Winter -5% to 10%

Spring -5% to 10%

Average annual relative humidity to generally decrease by -1% to -3% 2050

Summer -0.5% to -2%

Autumn -1% to -2%

Winter -1% to -3%

Spring -1% to -2%

Annual average wind speed to remain constant through to a 5% increase by 2050

Summer 0% to +2% (northern extent no change to -2%reduction)

Autumn 2% to +10% (northern extent no change to +2%)

Winter -5% to -10% (northern extent no change to +5%)

Spring remain constant

Annual average potential evapotranspiration will remain unchanged or increase by up to 4% by 2050